JPH11227057A - Manufacture of fiber reinforced plastic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method of a fiber reinforced plastic molding, by which the development of bubbles and voids in a molding can be remarkably checked, on the surface of which on fluffing of fiber develops and which is excellent in external appearance quality, can be obtained in the manufacturing method of the fiber reinforced plastic molding by a spray-up method. SOLUTION: The manufacturing method of the fiber reinforced plastic molding consists of a spraying of a resin composition and a fiber reinforcing material with a spraying-up machine on a mold and the following spraying of a calcium carbonate on the resultant resin composition and fiber reinforcing material. By spraying 5-50 pts.wt. of the calcium carbonate onto 50-95 pts.wt. of this resin composition, the total sum of the resin composition and the calcium carbonate turns to become to 100 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber-reinforced plastic (hereinafter, sometimes referred to as FRP) molded article using a spray-up machine.

[0002]

2. Description of the Related Art Among manufacturing methods of fiber-reinforced plastic molded products such as septic tanks and bathtubs, an open mold molding method such as a hand lay-up molding method or a spray-up molding method is used.
It is widely used because it is possible to produce many kinds and small quantities at room temperature and pressure, and the equipment cost is low. Among them, the spray-up molding method is to provide a gel coat layer on the surface of a previously manufactured mold as necessary, and apply a resin composition containing short fibers (fiber reinforcing material) such as glass fiber and unsaturated polyester to the surface. This is a method of forming the fiber reinforcement layer by spraying, but since large and small bubbles are mixed in the formed fiber reinforcement layer, when the fiber reinforcement layer is cured, the bubbles are removed using a defoaming roll. Work is indispensable.

[0003] In such a spray-up molding method, the fiber reinforcement and the resin composition forming the fiber reinforcement layer are scattered, and the solvent such as styrene monomer contained in the resin composition is scattered. Since the molding operation in an unfavorable environment is forced, the mechanization of the defoaming operation is difficult and it must be performed manually, and it takes a long time for molding and the skill is required for the defoaming operation. There was a problem with securing.

As a method for solving these problems, Japanese Patent Application Laid-Open No. 63-293038 discloses a method in which a fiber-reinforced plastic material, which is a kneaded product of a cut fiber and a resin composition, is pressure-fed into a hose by a pressure pump. There has been proposed a method for producing a fiber-reinforced plastic molded article that does not require defoaming work by applying the composition to the surface of a mold using an application nozzle. However, in this method, since the fibers cut to a length of 12.5 mm or more are entangled with each other to form a lump, it is difficult to uniformly apply the fiber reinforced plastic material to the surface of the mold. In addition, since the glass content is low, the strength of the molded product is reduced, and the viscosity of the kneaded material is increased, so that there is a problem that air bubbles are apt to be mixed in when applied to a molding die.

Japanese Patent Application Laid-Open No. Hei 5-239259 discloses that a resin composition containing a thermosetting resin, a spherical hollow filler and / or a star-like filler, and a fiber reinforced material are sprayed up using a spray-up machine. There has been proposed a method for producing a fiber-reinforced plastic molded article that does not require a defoaming step by using a roller or the like by applying it to the surface of a molding die. However, in this method, when the content of the fiber reinforcing material is high, the wetting of the resin composition and the fiber reinforcing material is reduced, and the generation of fuzz of the fibers on the surface and large bubbles inside the molded product remain, A defoaming step using a roller or the like is required. Further, when the amount of the fiber reinforcing material is small, there is a problem that the strength of the molded article is reduced although the fluff of the fibers and the large bubbles inside the molded article are reduced.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and in a method of manufacturing a fiber-reinforced plastic molded product by a spray-up method, generation of bubbles and cavities can be significantly suppressed. No fiber fuzz,
An object of the present invention is to provide a method for producing a fiber-reinforced plastic molded article which can obtain a molded article having excellent appearance quality and excellent strength.

[0007]

According to the present invention, there is provided a method of spraying a mixture obtained by combining a resin composition and a fiber reinforcing material in the air by a spray-up machine and spraying the mixture onto a molding die, and then spraying calcium carbonate thereon. And a method for producing a fiber-reinforced plastic molded article. Also, the present invention
The present invention relates to a method for producing the fiber-reinforced plastic molded article, wherein 5 to 50 parts by weight of calcium carbonate is sprayed on 50 to 95 parts by weight of the resin composition so that the total amount of the resin composition and calcium carbonate becomes 100 parts by weight. Further, the present invention, the total amount of the resin composition and calcium carbonate is 60 to 90 parts by weight and the amount of the fiber reinforcement is 10 to 40 parts by weight,
The total amount of the resin composition, calcium carbonate and fiber reinforcement is 1
The present invention relates to a method for producing the fiber-reinforced plastic molded product so as to be 00 parts by weight. In addition, the present invention relates to the method for producing a fiber-reinforced plastic molded article according to any one of the above, wherein the resin composition and the fiber reinforced material are sprayed onto a mold so that the mixture has a thickness of 1 to 3 mm.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the resin composition is not particularly limited as long as it is used for producing a fiber-reinforced plastic molded article such as a septic tank or a bathtub. , A vinyl ester resin composition and the like, and an unsaturated polyester resin composition is particularly preferable. The unsaturated polyester resin composition contains an unsaturated polyester, a polymerizable monomer, a curing agent, and, if necessary, various additives. The unsaturated polyester used in the present invention is obtained by reacting an acid component containing an unsaturated dibasic acid and / or an acid anhydride thereof and another polybasic acid used as required with an alcohol component by a known method. It can be obtained by

As the unsaturated dibasic acid and its acid anhydride, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride and the like are used, and two or more of these may be used in combination. The unsaturated dibasic acid and its acid anhydride are preferably used in an amount of 1 to 100 mol% in the acid component. In addition, these impart moderate hardness to the molded product,
Moreover, in order not to be too brittle, 20 to 90%
Mol%, more preferably 30 to 70 mol%
It is particularly preferred that they be used.

[0010] Other polybasic acids used as needed include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, trimellitic anhydride, succinic acid, azelaic acid, adipic acid, tetrahydrophthalic acid Acids, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, anthracene-maleic anhydride adduct, rosin-maleic anhydride adduct, hetic acid, hetic anhydride, tetrachlorophthalate Acid, tetrachlorophthalic anhydride, tetrabromophthalic acid, halogenated polybasic acids such as tetrabromophthalic anhydride, and the like. These may be used in combination of two or more. These are used by adjusting so that the entire acid component becomes 100% by weight.

As the alcohol component, ethylene glycol, diethylene glycol, propylene glycol,
Dipropylene glycol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol,
1,5-pentanediol, 1,6-hexanediol, triethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, dihydric alcohols such as hydrogenated bisphenol A, glycerin, trihydric alcohols such as trimethylolpropane, For example, a tetrahydric alcohol such as pentaerythritol is used. Two or more of these may be used in combination. The reaction between the acid component and the alcohol component is mainly performed by advancing a condensation reaction, and is advanced by desorbing a low-molecular compound such as water generated when both components react, to the outside of the system. The acid component and the alcohol component consist of one equivalent of the acid component and one alcohol component.
To 1.3 equivalents, preferably from 1.03 to 1.
It is more preferable to use 2 equivalents.

Examples of the polymerizable monomer include (meth) acrylic esters such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, divinylbenzene and methyl methacrylate [(meth) acrylic acid is methacrylic acid And acrylic acid. The same applies to the following), and vinyl acetate and the like are used, and two or more of these may be used in combination. The unsaturated polyester and the polymerizable monomer are 30 to 80% by weight of the former and 2
It is preferable to use 0 to 70% by weight.
It is particularly preferred to use 5% by weight and the latter 35-65% by weight.

[0013] Examples of the curing agent include organic peroxides such as methyl ethyl ketone peroxide, benzoyl peroxide, cumene hydroperoxide and lauroyl peroxide. This curing agent is usually added to the unsaturated polyester resin composition in an amount of 0.5 to 3.0.
It is blended in a ratio of weight%. It is preferable that the curing agent is separately prepared and mixed immediately before or at the time of using the resin composition. The curing agent is preferably used by dissolving it in an organic solvent such as xylene or toluene, or a liquid plasticizer such as dimethyl phthalate or dioctyl phthalate.

The unsaturated polyester composition obtained by dissolving the unsaturated polyester in the above polymerizable monomer and blending a curing agent, a curing accelerator, etc., may further contain, if necessary, hydroquinone, pyrocatechol, Polymerization inhibitors such as 6-di-tert-butylparacresol, dyes, plasticizers, ultraviolet absorbers, silica powder, asbestos powder, hydrogenated castor oil, known thixotropic agents such as fatty acid amides, calcium carbonate, titanium, etc. Filler with a large specific gravity, silica balloon,
Various additives such as a filler having a small specific gravity such as a glass balloon, a stabilizer, an antifoaming agent, and a leveling agent may be blended.

Examples of the curing accelerator include metal soaps such as cobalt naphthenate and cobalt octenoate; quaternary ammonium salts such as dimethylbenzylammonium chloride; β-diketones such as acetylacetone; dimethylaniline; -Amines such as toluidine and triethanolamine. The blending ratio of the curing accelerator is not particularly limited and is appropriately determined depending on the required curability, but is preferably 0.005 to 5 based on the total amount of the unsaturated polyester and the polymerizable monomer. weight%
used.

The production of the FRP molded article of the present invention is carried out by a spray-up molding method. In this method, a release agent is applied and a gel coat layer is formed, if necessary, on the surface of a previously produced mold. Then, a fiber reinforced material and a resin composition are sprayed on the surface, and defoaming such as rolling using an aluminum or pig hair defoaming roll is performed, followed by curing to obtain an FRP molded product. The fiber reinforcement and the resin composition may be sprayed separately but simultaneously, or the fiber reinforcement and the resin composition may be sprayed from one spray gun so as to merge in the air.

The fiber reinforcement is not particularly limited, and various known fiber reinforcements and fiber reinforcements surface-treated with a coupling agent can be used. Examples thereof include glass fiber, carbon fiber, and organic synthetic fiber. Whiskers, ceramic fibers, metal fibers, natural plant fibers and the like. In consideration of the strength and moldability of the molded product, the amount of the fiber reinforcing material should be 10 to 40 parts by weight based on the total amount of the resin composition and calcium carbonate of 60 to 90 parts by weight. , Preferably 15 to 35 parts by weight. The mixing ratio is determined so that the total amount of the resin composition, calcium carbonate, and fiber reinforcing material is 100 parts by weight. Further, the total amount of the resin composition and the fiber reinforcement is 2 to 15
It is preferable to spray at a discharge rate of kg / min.

As the fiber reinforcing material to be sprayed, glass roving is preferable. The length of the fiber reinforcing material (cut length of the glass roving) is preferably in the range of 5 to 50 mm, particularly from the viewpoint of preventing dripping of the mixture sprayed on the mold and reducing entrapment of air bubbles. It is preferably 40 mm, more preferably 12 to 25 mm.

In the present invention, the distance between the mold and the spray gun is not particularly limited. However, if the distance is too long, air bubbles are likely to be mixed, and if the distance is too short, the resin composition and the fiber reinforcing material are scattered. 400 ~ 1200mm
And more preferably 500 to 700 mm.

Further, from the viewpoint of reducing the entrapment of air bubbles of the mixture blown to the mold and further improving the foam breaking property, the thickness of each spraying of the resin composition and the fiber reinforcing material to the mold is 1 to 1. It is preferable to spray calcium carbonate after making the thickness 3 mm. The calcium carbonate used in the present invention is not particularly limited with respect to the place of collection and the method of treatment, but in consideration of the porosity and strength of the molded article, the particle size is 10 to 10.
3000 μm is preferred, and 50 to 2000 μm is particularly preferred.

The amount of calcium carbonate used is preferably 5 to 50 parts by weight based on 50 to 95 parts by weight of the resin composition, and 20 to 40 parts by weight based on 60 to 80 parts by weight of the resin composition. It is particularly preferred to use parts by weight. However, the total amount of the resin composition and calcium carbonate is determined so as to be 100 parts by weight. If the proportion of calcium carbonate is out of the above range, many voids remain in the molded product, so that the porosity increases and the strength tends to decrease. In the present invention, the method of spraying calcium carbonate is not particularly limited, and a spray gun or the like can be used as necessary. The discharge amount at the time of spraying the calcium carbonate is 0.1 to 0.1 in consideration of the entrapment of air bubbles and the foam breaking property.
Preferably, it is 5 kg / min. After spraying the resin composition and the fiber reinforcing material or a mixture thereof, the calcium carbonate is sprayed preferably within 10 minutes, more preferably within 5 minutes. If the spraying of calcium carbonate is too slow, the wetting of calcium carbonate and the resin composition tends to be poor. If the spraying of calcium carbonate is too early, there is no effect of breaking bubbles. Therefore, it is not necessary to rush too quickly, and the spraying may be performed after a lapse of 1 to 2 minutes after spraying the mixture of the resin composition and the fiber reinforcing material.

[0022]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In the examples, “parts” and “%” indicate “parts by weight” and “% by weight”, respectively, unless otherwise specified.

Reference Example (Production of unsaturated polyester composition) 5 mol of maleic anhydride, 5 mol of phthalic anhydride and 10.5 mol of propylene glycol were mixed with a stirrer, a condenser,
The mixture was charged into a 2-liter four-necked flask equipped with a thermometer and an inert gas inlet, and reacted at 210 ° C. in a conventional manner under nitrogen gas introduction. To 55 parts of the obtained unsaturated polyester, 45 parts of styrene and 200 ppm of hydroquinone based on this mixture were added to obtain an unsaturated polyester composition.

Examples 1 to 3 100 parts of the unsaturated polyester composition prepared in Reference Examples,
As a thixotropic agent, 1.8 parts of silica powder (trade name: Aerosil # 200, manufactured by Nippon Aerosil Co., Ltd.), 0.4 parts of 6% cobalt naphthenate, 0.01 parts of 5% copper naphthenate and 0.1 parts of dimethylaniline 0.1 Parts were mixed and dissolved to obtain a viscosity of 0.4 Pa · S,
A resin composition for molding having a degree of thixotropicity of 4.0 and a gelling time of 15 minutes was obtained. Viscosity, thixotropic degree and gel time are JIS
It was measured according to K6901. When measuring the gelation time, 55% of the resin composition was used as a curing agent.
A 1.0% solution of methyl ethyl ketone peroxide in dimethyl phthalate was used.

A fiber reinforced material consisting of a 55% methyl ethyl ketone peroxide solution in dimethyl phthalate and a glass roving at a ratio of 1% of a curing agent to the resin composition (glass roving manufactured by Nitto Boseki Co., Ltd., trade name: RS23)
0-FG610, used in an amount of 33% based on the total amount of the resin composition and the fiber reinforcing material) in a molding die under the conditions shown in Table 1, and using a spray gun to produce calcium carbonate under the conditions shown in Table 1. Sprayed. Immediately thereafter, a defoaming step is performed using a pig hair spiral roll (outer diameter: 50 mm, length: 150 mm), which is rolled a predetermined number of times. After curing at room temperature, the molded article is removed from the fiber-reinforced plastic molded article. Obtained.
The mold at this time was worked upright. The presence or absence of fluffing due to fibers in the obtained molded article was visually observed, and a flat portion of the molded article was cut out, and the porosity was measured in accordance with JIS K7053 and the strength was measured in accordance with JIS K7055. It was shown to.

[0026]

[Table 1]

Comparative Examples 1 and 2 FRP molded articles were produced in the same manner as in the above Examples under the conditions shown in Table 2, and in the same manner as in the Examples, the presence or absence of fluffing due to the fibers of the molded articles, the porosity, and the strength were measured. Table 2 shows the measurement results.

[0028]

[Table 2]

[0029]

According to the method of the present invention, even if the defoaming step is simplified (for example, the number of rolls for defoaming is reduced), the incorporation of air bubbles can be prevented, and the fluffing of fibers can be prevented. Thus, a molded article having excellent strength can be obtained, and quality and productivity can be improved, such as prevention of defects due to poor defoaming and reduction of manufacturing costs.

Claims (4)

[Claims] 1. A method for producing a fiber-reinforced plastic molded article, comprising spraying a resin composition and a fiber reinforcing material onto a mold using a spray-up machine, and then spraying calcium carbonate thereon. 2. The fiber according to claim 1, wherein 5 to 50 parts by weight of calcium carbonate is sprayed on 50 to 95 parts by weight of the resin composition so that the total amount of the resin composition and calcium carbonate is 100 parts by weight. Manufacturing method for reinforced plastic molded products. 3. The total amount of the resin composition and calcium carbonate is 6.
The fiber reinforcement according to claim 1, wherein the amount of the fiber reinforcement is 10 to 40 parts by weight based on 0 to 90 parts by weight, and the total amount of the resin composition, calcium carbonate, and the fiber reinforcement is 100 parts by weight. Manufacturing method of plastic molded products. 4. The method for producing a fiber-reinforced plastic molded product according to claim 1, wherein the resin composition and the fiber-reinforced material are sprayed on a mold so that the mixture has a thickness of 1 to 3 mm.